An evaluation of two heavier-than-water internal limiting membrane-specific dyes during macular hole surgery

To evaluate the staining characteristics and effect on internal limiting membrane (ILM) histology of two heavier-than-water ILM-specific dyes during macular hole surgery: acid violet 17 combined with 5 % mannitol (AV17-M) and brilliant blue G with 4 % polyethylene glycol (BBG-P). Single-centre observational comparative cohort study. The ILM of consecutive patients undergoing surgery for idiopathic macular hole were stained with BBG-P and AV17-M for 10 s each. The ILMs were retrieved and examined with electron microscopy. The extent of retinal and vitreous side debris was scored. Surgical videos were used to assess the staining contrast effect by measuring the Euclidean distance in the CIELAB colour space between stained and unstained retinas after peeling. 51 consecutive patients were studied with 25 in the AV17-M group and 26 in the BBG-P group. The mean age was 71 years with no significant difference between the groups. The amount of retinal side tissue was greater on the BBG-P-stained ILMs compared to the AV17-M-stained ILMs (30.2 versus 19.6 %, p < 0.001). There was a difference in the CIELAB colour space separation distance between stained and peeled retinas (5.89 versus 3.97, p = 0.01) in favour of BBG-P. Visual outcomes between the two groups were similar (logMAR visual acuity 0.40 versus 0.38, p = 0.74). Both stains were successfully used to peel the ILM with comparable outcomes. AV17-M resulted in less retinal debris than BBG-P, suggesting an altered and potentially beneficial ILM cleavage plane from the retina but with lowered staining contrast than BBG-PEG.